Reflective liquid crystal polarization gratings with wide angle and high diffraction efficiency

A highly diffraction efficiency reflective liquid crystal polarization grating (LCPG) was fabricated by employing two orthogonally circularly polarized beams with a 266 nm laser. The reflective LCPG sample works at the wavelength of 1064 nm. The diffraction efficiency of the reflective LCPG sample was evaluated using hand-polarized light at 1064 nm laser. It was shown that a remarkable diffraction efficiency of 97.4% was achieved when the beam was incident normally. Moreover, the diffraction efficiency remained above 90% within the incident range of ±20°. Subsequently, we conducted the laser damage test on the reflective LCPG using nanosecond pulses at 1064 nm generated by Nd:YAG laser. The test results indicated that laser induced damage threshold was 9.1 J/cm² (12 ns). This research provides valuable insights into design and fabrication of reflective LCPGs. This device has potential applications such as laser radar, beam splitting and combining, spectral analysis, displacement sensor, raster projection display and high-intensity laser systems.